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GB677970A - Improvements in or relating to electric frequency modulating circuits - Google Patents

Improvements in or relating to electric frequency modulating circuits

Info

Publication number
GB677970A
GB677970A GB3681/51A GB368151A GB677970A GB 677970 A GB677970 A GB 677970A GB 3681/51 A GB3681/51 A GB 3681/51A GB 368151 A GB368151 A GB 368151A GB 677970 A GB677970 A GB 677970A
Authority
GB
United Kingdom
Prior art keywords
wave
frequency
band
sources
mixed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB3681/51A
Inventor
Thomas Symington Mcleod
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB677970A publication Critical patent/GB677970A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details
    • H03C3/06—Means for changing frequency deviation

Landscapes

  • Superheterodyne Receivers (AREA)
  • Transmitters (AREA)

Abstract

677,970. Frequency modulation. STANDARD TELEPHONES & CABLES, Ltd. Feb. 15, 1951, No. 3681/51. Class 40 (v). With the object of raising the frequency deviation of a frequencymodulated wave without making a proportional increase in the mean carrier frequency, the primary FM wave is mixed with waves from two further sources, the upper side-band is selected from one of the mixer outputs, and the lower side-band from the other, the two selected side-bands are mixed with each other, and the lower side-band selected to provide the output. As shown, a FM wave is produced by applying the signal through an amplifier 1 to give a frequency deviation f in opposite senses to waves of frequencies F1, F2 generated by sources 2, 3. The outputs are mixed at 4, and the difference frequency, F1 - F2 + 2f, selected by filter 5, constitutes the primary FM wave. According to the invention, this wave is mixed at 6 and 7 with waves of frequencies F3, F4 respectively generated by sources 8, 9. The upper side-band is selected by a filter 10 from the output of mixer 6, and the lower side-band from the output of mixer 7 by a filter 11. The selected side-bands are mixed at 12, and the lower sideband selected by a filter 13 provides an output FM wave whose deviation is double that of the primary FM wave and whose mean frequency is changed to a less degree. Further, similar frequency-changing stages may be provided, the mixing waves being supplied by the sources 8, 9 or by other sources of different frequency.
GB3681/51A 1951-02-15 1951-02-15 Improvements in or relating to electric frequency modulating circuits Expired GB677970A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB303099X 1951-02-15

Publications (1)

Publication Number Publication Date
GB677970A true GB677970A (en) 1952-08-27

Family

ID=10305608

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3681/51A Expired GB677970A (en) 1951-02-15 1951-02-15 Improvements in or relating to electric frequency modulating circuits

Country Status (3)

Country Link
US (1) US2735983A (en)
CH (1) CH303099A (en)
GB (1) GB677970A (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE519917A (en) * 1952-05-14
US3044017A (en) * 1956-12-31 1962-07-10 Bell Telephone Labor Inc Microwave carrier logic circuits
US3002160A (en) * 1958-01-29 1961-09-26 Gen Electric Phase modulation system
US3105937A (en) * 1959-11-23 1963-10-01 Gen Dynamics Corp Carrier transmission system for reducing impulse noise
US3195059A (en) * 1960-07-08 1965-07-13 Itt Demodulator system for angularly modulated signals having improved noise immunity
NL292145A (en) * 1962-04-30
NL292106A (en) * 1962-05-04
US3249897A (en) * 1963-03-26 1966-05-03 Theodore R Trilling Frequency modulator having voltage variable capacitance means

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2523222A (en) * 1947-04-05 1950-09-19 Raytheon Mfg Co Frequency modulation system
NL141942B (en) * 1947-08-19 Meier Hermann Ernst STONE TO LAY IN CONNECTION.
US2526347A (en) * 1947-09-30 1950-10-17 Union Switch & Signal Co Method of and means for producing frequency modulation

Also Published As

Publication number Publication date
US2735983A (en) 1956-02-21
CH303099A (en) 1954-11-15

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